The annual meeting of IDCNS was held 22-23 August 1996 at the
Bureau
International des Poids et Mesures (BIPM) in Sèvres, France. The
meeting
followed so closely on the conclusion of the IUCr Seattle Congress
that neither the IUCr Representative nor the Alternate were able to
participate. Nevertheless, the strong objections presented by the IUCr,
at
earlier meetings of IDCNS, to the 1994 proposal of the Comité
Consultative
d'Unités (CCU) of BIPM to deprecate the Ångström were
set forth very
effectively by the Chair of IDCNS at the April 1996 meeting of CCU.
Among
the resulting recommendations made by CCU to the Comité
International des
Poids et Mesures (CIPM) for final action on this matter was that Chapter
IV
(entitled Units outside the International
System) in the next edition of
the authoritative brochure Le Système
International d'Unités (SI), to be
published in 1997, should be substantially revised in a major change of
style. Table 10 in this chapter will have the revised heading `Other
units
currently accepted for use with the SI. These units should be expressed
in
relation to the SI in every document in which they are used.' There will
be
no further deprecatory remarks. Table 10 will contain the following
units:
are, hectare, Ångström, bar, barn, nautical mile and knot,
and will give
their relation to the SI. The practical consequence of this decision is
that Ångströms may continue to be used without being in
breach of anything
said in the SI Brochure, provided only that such authors include a
footnote
in every paper that makes use of Ångströms along the lines:
`1 Å =
10-10 m'. The IUCr has
interpreted this proviso by printing the statement `Units:
The International System of Units (SI) is used in all IUCr journals
except
that the Ångström (symbol Å, defined as
10-10 m) is generally
preferred
to the nanometre (nm) or picometre (pm) as the appropriate unit of
length.'
in each issue of all journals.

Authority to act in all matters between
nations concerning measurement standards has been given jointly to the
Conférence Générale des Poids et Mesures, the CIPM
and the BIPM by the
Convention du Mètre. This Convention, which dates to 1875, is a
diplomatic
treaty that has now been signed by 48 nations.

Among other matters discussed in Sèvres of interest to the
IUCr, the
third edition of IUPAC's Green Book Quantities, Units
and Symbols in
Physical Chemistry is expected to be published in
1998. It will contain a
new section on uncertainties, also new material on surface science, NMR
and
nonlinear spectroscopy. A further development in the consideration of
prefixes for binary systems is the
proposal by the International Electrotechnical Commission to adopt the
following: 210 = kibi (kilobinary), symbol
Ki; 220 = mebi (megabinary),
symbol Mi; 230 = gibi (gigabinary), symbol
Gi and 240 = tebi
(terabinary), symbol Ti. Comment by crystallographers on this proposal
is
invited and should be sent either to the Representative or the Alternate
Representative.

A total of 39 nomenclature reports originating in the Divisions
and
Commissions of IUPAC were received by the Representative in the course
of the
year. Reports containing matters likely to be of interest or concern to
the
IUCr were reviewed with care and corrections made where necessary.
Following revision, as required by IDCNS, all accepted nomenclature
reports
are published in Pure Appl. Chem. and
constitute the current nomenclature
policy of IUPAC.